To deal with challenges of wireless broadband technologies and ensure leading advantages of 3rd Generation Partnership Project (3GPP) networks, the 3GPP has initiated a Long Term Evolution (LTE) program for mobile communications networks at the end of 2004. A new mobile communications network architecture is defined under the guidance of the LTE program. The new mobile communications network architecture is flatter than existing 2G and 3G networks, and retains only a packet switched domain (PS); therefore, this network architecture may be referred to as an evolved packet system (EPS). A network architecture of the EPS may be shown in FIG. 1. FIG. 1 is a schematic diagram of an EPS network architecture disclosed in the prior art. In the EPS network architecture shown in FIG. 1, an evolved packet core (EPC) mainly includes three logical functional entities: a mobility management entity (MME), a serving gateway (S-GW), and a packet data network gateway (P-GW). The MME is mainly responsible for non-access stratum (NAS) signaling and NAS signaling encryption, roaming and tracking, allocation of a temporary subscriber identity, a security function, and the like. The MME is corresponding to a control plane part of a serving GPRS support node (SGSN) in a GERAN/UTRAN network. The S-GW is mainly responsible for functions such as a local mobility anchor, a mobility anchor in a 3GPP system, and lawful interception of related information. The P-GW is mainly responsible for related functions such as policy enforcement and charging and lawful interception.
In the EPS network architecture shown in FIG. 1, when a user equipment (UE) accesses the EPC, based on access point name (APN) information (which is configured by default or provided by the UE), a PDN connection (also referred to as a “session connection”) to which an APN is directed needs to be first established for the UE. In addition, a corresponding IP address is provided for the UE in a session connection creation process. A first bearer created in the session connection is referred to as a default bearer (which is kept in an active state within an entire session connection period), and a subsequently created bearer is a dedicated bearer. When the UE performs a service, flows having a same UE IP address and flowing to a same PDN (that is, having a same APN attribute) converge into one session connection. Further, flows having a same quality of service (QoS) attribute converge into one bearer.
Currently, based on the EPS network architecture shown in FIG. 1, an implementation architecture of selected IP traffic offload (SIPTO) may be shown in FIG. 2. FIG. 2 is a schematic diagram of an implementation architecture of SIPTO disclosed in the prior art. In the 3GPP standard, a concept of offloading a service data flow packet from an access network or a location near an access network to a particular PDN is referred to as SIPTO. A basic principle of SIPTO is as follows: A gateway is deployed at a location near the access network to execute a SIPTO policy. The gateway is a local gateway (L-GW). An operator sets a particular APN for a SIPTO service data flow packet. When a PDN connection is being established, based on the particular APN, a SGSN/MME selects an L-GW, and the L-GW sends all received uplink service data flow packets of a service directly to a PDN. However, in the implementation architecture shown in FIG. 2, during SIPTO policy enforcement, the UE needs to configure a correspondence between an application (APP) and an APN, and all applications in the PDN to which the particular APN is directed need to be deployed at a location near a base station. Consequently, the APPs in the PDN cannot be differentially deployed as required. It can be learned that an existing APN-based SIPTO implementation solution has problems of poor applicability and insufficient flexibility in service data flow packet deployment.